The present invention relates to dehydrated slices of vegetables and fruits which are adapted e.g. to be re-hydrated under maintenance of their natural appearance, and to a processing method. Such dehydrated slices can also be used in the dried state e.g. as a low-fat snack.
The modern consumers' nutrition habits lately focus more and more on healthy, fresh and tasty food, which should be provided at any time of the day, being quickly prepared to provide a complete and nourishing meal. Food such as soups, sauces and the like shall be prepared fast, requiring only a minimum of preparation steps, tasting or looking freshly prepared at the same time. Accordingly, components such as fruit, vegetables or mushrooms which are provided in convenience products or foods, respectively, shall be processed to permit storage, particularly long-term storage, being maintained naturally and fresh looking and tasty anyway, and, hence, having an esthetic appearance.
Taste, form and properties of processed foods change significantly depending on their processing. A variety of processing methods is known to provide healthy or naturally looking foods.
U.S. Pat. No. 6,977,090 to R. J. Petcavich, teaches methods for preserving the natural color and appearance of fresh and minimally processed produce, aiming to inhibit desiccation or discoloration such as white blushing, e.g., of the processed fruit and vegetables by providing the fruit or vegetable with a trehalose or sugar coating.
A method for non-fry cooking and its uses is taught in US 2005/0013910 to Yasou Takeuchi et al., relating particularly to a method for non-fry cooking, comprising a step of heating and dehydrating a food material using an aqueous trehalose solution with a relatively high temperature and concentration. A non-fried and thus fat reduced product is obtained by the method provided; furthermore an agent for non-fried cooking comprising trehalose as an effective ingredient is disclosed.
In US 2003194479 to Yasou Takeuchi et. al, a process for producing processed foods is disclosed, describing the steps of contacting raw food material(s) with saccharide (s) in a solid or a liquid form, providing the uptake of saccharide(s) by an intact food material. Said process is performed without blanching and then heating the resulting mixture by one or more heating methods selecting form the group consisting of steaming, baking, frying, and microwaving. Takeuchi et al. aim for an effective exertion of flavor and taste of said food materials, and providing a superior preservative stability of the processed material.
However, the vegetables and fruits, or pieces therefrom, preserved by the methods described in the state of the art have sustained a loss of their fresh-looking appearance which is based substantially on three-dimensional shrinkage and rippled surfaces, sometimes accompanied by a change of color. A slice of vegetable, e.g., will—according to a widely known experience—become wrinkled and uneven and potentially brownish after having been subjected to a dehydrating preserving process described in the state of the art.
Extensive shrinkage in all dimensions leads to a hard texture after rehydration, presumably because fibres form compact structures that do not easily take up water and unfold again.